A furnace grate in an incinerator furnace, typically consists of horizontally or obliquely arranged overlapping rows of grate bars. These rows of grate bars are placed one behind the other, in the same manner that roofing shingles overlap one another. Every second row of grate bars has a drive associated with it for moving the material to be burned and for improving the raking action. The movement of the rows of grate bars is accomplished by connecting several rows of grate bars and by actuating the rows of grate bars with a single drive. A grate bar of the above-mentioned type is disclosed in German Patent 24 46 724, in which a cylinder, positioned behind a carriage carrying a plurality of moveable rows of grate bars seated on a grate bar support, moves the carriage in the feed direction.
The drives and moving parts of the furnace grate are positioned underneath the grate and within the undergrate blast or air region. The above arrangement for moving parts and drives is especially problematic since, within the undergrate air region, they are exposed to high temperatures and the likehood exists that burning material will fall between the grate bars so as to render the drives and moving parts susceptible to failure. Because the devices and moving parts are located beneath the grate and within the undergrate air region, they are inaccessible during operation of the furnace, and, therefore, cannot be checked or serviced so as to render these devices and moving parts undependable.
German Patent 30 07 678, discloses an arrangement wherein the grate bar supports are located on torsion shafts which extend outside of the undergrate blast region, so that the essential parts of the drive, such as the stroke cylinder, swing rod and linear guides are positioned outside the walls of the furnace. However, the numerous torsion shafts, and the numerous rotary, swivel and linear guides lying outside of the furnace walls, as well as the grate bar joints positioned within the furnace present a problem. A comparison of the prior art cited above shows that several hundred moveable locations per grate are present in the drive chain.